Windows GDI is an interface that “… enables applications to use graphics and formatted text on both the video display and the printer.” GDI functions can be used to draw lines, text, curves and other graphical elements.

The fix works by injecting itself to all processes loading user32.dll. It patches the Escape() function in gci32.dll, revoking WMF’s SETABORT escape sequence that is the root of the problem. [ Hex blog post ]